It`s time for Canada to revise its official fuel consumption ratings for new vehicles. Identical vehicles sold in Canada and the U.S. have government approved fuel consumption ratings that are 15-20 percent apart. The Canadian figures consistently promise better mileage than the vehicle is able to deliver in real-world driving. For example, Toyota`s smallest car, the Yaris hatchback, is rated at 5.5 L/100 km Highway in Canada, but a significantly higher (22% percent) 6.7 L/100 km in the United States. That works out to about seven miles per Canadian gallon less using the the U.S. rating, which is much closer to what Yaris owners report their vehicles actually consume. CBC and the APA selected 13 popular 2012 models and compared their Canadian and U.S. fuel consumption ratings.

Fuel consumption ratings are derived by driving the vehicle in a laboratory setting on a "rolling road" under ideal conditions. The air temperature is comfortable and a cooling breeze soothes the engine. Acceleration is leisurely, and the highway speed of 90 km/h is about 20 percent slower than the average on Canadian highways. The result is an optimistic projection, with a theoretical range in highway driving of 700-800 km on a tank of gas. Most vehicles tested by the APA manage 500-650 km, so the consumer is being "shorted" about 100 km per tankful compared to the numbers in car ads. Dealers and the carmakers know this, but they hide behind the veneer of "government" or "Transport Canada" approval for the numbers to make their pitch.

Canada and the United States used the same test procedure to calculate City and Highway fuel consumption ratings. In 2007, the Americans modified their calculation to take into account more realistic driving speeds, temperatures and the use of air conditioning. As a consequence, posted consumption increased by 15-25 percent for most vehicles, and consumer complaints in the U.S about the ratings abated.

CBC`s Go Public recently discovered there is no government testing in Canada. It`s performed by the carmaker for the North American market and then two numbers are supplied: a rosy one to Canadian authorities, and a more accurate one to U.S. authorities. (You can view the comparison on the CBC website.) Canada relies exclusively on the Americans to spot check the carmakers` fuel consumption ratings -- but Canada doesn`t use the more realistic American fuel consumption figures. Canada needs to bring its fuel consumption ratings closer to reality. The easiest and least expensive solution would be to apply a metric version of the U.S. fuel consumption rating.

For provinces with green levies, APA recommends accepting the current, optimistic, number for gaz guzzler penalties, so that the change is taxation neutral. Alternatively, the provincial guidelines could be modified to reflect the new, more realistic numbers, so that the public is not penalized when several vehicles move into higher consumption brackets.

What you can do:

Use the City rating as a prediction of what you will get in mixed driving. The City figure is optimistic compared to actual fuel consumption in real urban driving, but it`s a helpful average for overall fuel consumption in city and highway driving. The APA has been using only the City number for years in its vehicle ratings.

When shopping for a vehicle, use the U.S. fuel consumption figures, which are also listed in metric form in the U.S. Fuel Economy Guide